منابع مشابه
The Transparency of Solar Coronal Active Regions
Resonance scattering has often been invoked to explain the disagreement between the observed and predicted line ratios of Fe XVII λ15.01 to Fe XVII λ15.26 (the “3C/3D” ratio). In this process photons of λ15.01, with its much higher oscillator strength, are preferentially scattered out of the line of sight, thus reducing the observed line ratio. Recent laboratory measurements, however, have foun...
متن کاملAnomalous Coronal Neon Abundances in Quiescent Solar Active Regions
The systematic di†erences between the solar photospheric and coronal composition are generally thought to be related to the Ðrst ionization potential (FIP) of the trace elements. While there are ample data showing that this is a signiÐcant factor, there is a growing body of observational evidence that a simple, FIP-based formula is not the whole story for coronal abundances. One of the most tro...
متن کاملModelling nanoflares in active regions and implications for coronal heating mechanisms.
Recent observations from the Hinode and Solar Dynamics Observatory spacecraft have provided major advances in understanding the heating of solar active regions (ARs). For ARs comprising many magnetic strands or sub-loops heated by small, impulsive events (nanoflares), it is suggested that (i) the time between individual nanoflares in a magnetic strand is 500-2000 s, (ii) a weak 'hot' component ...
متن کاملCharacteristics of Anemone Active Regions Appearing in Coronal Holes Observed with Yohkoh Soft X-ray Telescope
Coronal structure of active regions appearing in coronal holes is studied by using the data obtained with the Soft X-Ray Telescope (SXT) aboard Yohkoh from 1991 November to 1993 March. The following characteristics are found; Many of active regions appearing in coronal holes show a structure that looks like a “sea-anemone”. Such active regions are called anemone ARs. About oneforth of all activ...
متن کاملAutomated Temperature and Emission Measure Analysis of Coronal Loops and Active Regions Observed with AIA/SDO
We developed numerical codes designed for automated analysis of AIA/SDO image datasets in the 6 coronal filters, including: (i) coalignment test between different wavelengths with measurements of the altitude of the EUV-absorbing chromosphere, (ii) self-calibration by empirical correction of instrumental response functions, (iii) automated generation of differential emission measure (DEM) distr...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1975
ISSN: 0074-1809
DOI: 10.1017/s0074180900071606